5
2
AVB Networking
2.2
What is AVB?
StudioLive™ Series III
AVB Networking Guide
Let’s take a quick look at a microphone signal’s signal flow on a simple AVB network.
In the example below, the microphone’s signal is represented by the blue line:
mic
Mixer
Monitoring
Stage Box
AVB Switch
Link
PoE
Blue= PoE On
(Hold to toggle)
White= PoE Off
1
2
3
4
5
SW
5E
AVB SWITCH WITH P
o
E
PoE
Link
PoE
1
2
3
4
5
Network
As you can see, tracing a device’s signal path becomes a little more complex
because the routing is handled entirely in the digital domain. But because
experienced audio engineers understand signal flow and are used to
troubleshooting problems in an analog system at the various points of
weakness, configuring an audio network becomes that much easier.
2.2
What is AVB?
AVB (Audio Video Bridging) is an extension to the Ethernet standard designed to
provide guaranteed quality of service, which simply means that audio samples will
reach their destinations on time. AVB allows you to create a single network for audio,
video, and other data like control information, using an AVB-compatible switch.
This enables you to mix normal network data and audio network data on the same
network, making it easier to create both simple and complex networks. Numerous
audio companies have adopted it, and more companies are adding it all the time.
Audio-over-Ethernet has become increasingly attractive in Pro Audio
applications especially for distribution in large-scale systems, such as those
used in sporting venues, concert halls, and education institutions. The problem
is that most solutions are proprietary, making these systems too expensive
and too complex for most smaller applications. AVB is intended to change
that by providing an open source collection of IEEE standards available
for use by the pro audio market and its manufacturing community.
AVB networking offers several features that make it ideal for audio applications:
•
Long, light cable runs. A single lightweight CAT5e or CAT6 cable can
be run up to 100 meters (328 feet). This makes it easy to have audio
I/O located in different rooms (or even different venues in the same
building) and run multichannel audio between them in real time.
•
Low, predictable latency. AVB provides latency of no longer than 2 ms
sending an audio stream point-to-point over up to seven “hops” (trips through
switches or other devices) on a 100 Mbps network. With higher speed
networks, many AVB devices support lower latencies and additional hops.
Please note that while PreSonus AVB products operate at faster Gigabit network
speeds, they are currently fixed to 2 ms of latency.
•
Scalable, with high channel counts. AVB’s bandwidth is sufficient to carry
hundreds of real-time channels using a single Ethernet cable. This offers the
future possibility of expanding your system with additional devices that contain
different kinds of audio I/O, multiple controllers, and other useful functions.
